#
# fusion.db.view
#
# Copyright 2007 Helsinki Institute for Information Technology
# and the authors.
#
# Authors: Ken Rimey <rimey@hiit.fi>
#

# Permission is hereby granted, free of charge, to any person
# obtaining a copy of this software and associated documentation files
# (the "Software"), to deal in the Software without restriction,
# including without limitation the rights to use, copy, modify, merge,
# publish, distribute, sublicense, and/or sell copies of the Software,
# and to permit persons to whom the Software is furnished to do so,
# subject to the following conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
# IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
# CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
# TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
# SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

from UserDict import DictMixin

class View(DictMixin):
    def __init__(self, db, collection, base_path, my_identity=None,
                 as_text=False):
        self.db = db
        self.collection = collection
        self.base_path = base_path
        self.identity = my_identity
        self.as_text = as_text

    def __getitem__(self, path):
        path = self.base_path + '/' + path
        value = self.db.get(self.collection, path, as_text=self.as_text)
        if value is None:
            raise KeyError
        else:
            return value

    def __setitem__(self, path, value):
        if self.identity is None:
            raise ValueError('Cannot write to view'
                             ' if identity was not provided.')

        path = self.base_path + '/' + path
        return self.db.put(self.collection, path, value, self.identity)

    def keys(self):
        return self.db.keys(self.collection, self.base_path)
